Originally Posted by tigon_ridge
Why do so few manufacturers (actually, there's only 1?) implement active crossovers?
Because most headphones are full-range, and no crossover is the best crossover.
That would resolve all of the flaws of traditional multi-driver + passive XO design philosophy, would it not?
I'm not sure. A properly designed passive crossover should work very well. Just because they make them active doesn't mean they get it right.
There's also the question of increasing cost.
The biggest hurdle that I can see here is in getting manufacturers to agree on standardization; that way, amplifiers from manufacturer X will be compatible with DACs from manufacturer Y, and IEMs from manufacturer Z.
Or every manufacturers just uses proprietary stuff so they can kinda force you to buy all their components.
It seems Jerry Harvey found a way to achieve a new level of phase alignment without going down the active XO route. He calls it Freqphase, which I'm not sure whether JH has patented, or is just a label he uses to describe his technique.
There have been IEMs with clean phase response long before Freqphase, yet he claims "Freqphase™ creates the world's first phase-coherent earphone".
On the website it says patent pending but I guess it's something as simple as moving the drivers a bit back to ensure sound arrives more coherently at the eardrum. Afaik it's still passive crossovers.